How effective is the patch at preventing pregnancy?

<p>The patch can be very effective—but only when it&rsquo;s changed on time. With perfect use, the patch is more than 99% effective. Typical use is far more likely, however, and that&rsquo;s around 91%.</p> <p>In other words:</p> <p>Of those women who use the patch exactly as directed, fewer than 1 in 100 will experience an accidental pregnancy during the first year of using this method. </p> <p>Of those women who do not use the patch exactly as directed, about 9 in 100 will experience an accidental pregnancy during the first year of using this method. </p>